The problem: A rectangle is 60 x 80 (area is 4800), find what the width of a uniform border exactly half the area would be.
I came up with the equation 2400 = (80-2x)(60-2x) which then expands into 0 = 4x^2-280x+4800, I then did the quadratic equation which gave me the answer of 30 and 40 but both of these dont work because if it were 30 (6-2(30)) would equal 0 and if it were 40 (80-2(4)) would equal 0 and a dimension can't be 0.
Diagram i made
(this is how i came up with the equation)
I came up with the equation 2400 = (80-2x)(60-2x) which then expands into 0 = 4x^2-280x+4800, I then did the quadratic equation which gave me the answer of 30 and 40 but both of these dont work because if it were 30 (6-2(30)) would equal 0 and if it were 40 (80-2(4)) would equal 0 and a dimension can't be 0.
Diagram i made